A comparable positioning system is known from DE-OS No. 30 24 109 corresponding to U.S. Pat. No. 4,455,543. The state of the art describes a positioning system including an anchor plate on an actuator which may be shifted back and forth between two actuating solenoids. In one operating position, the anchor plate is held by one of the actuating solenoids, while in the other operating position the anchor plate is held by another actuating solenoid situated opposite its counterpart.
While the anchor plate is being held in one operating position as a result of current flow through one actuating solenoid, the other actuating solenoid is simultaneously energized. The operating positions are changed due to the fact that the actuating solenoid within whose attractive field the anchor plate is situated is de-energized, whereby the spring-loaded anchor plate is driven toward and seized by the other actuating solenoid.
The precise moment of switchover is thus defined by the de-energizing, and not by the energizing, of an actuating solenoid.
A problem is raised by the fact that, due to eddy currents generated in the solenoid core, the decay of the magnetic field cannot be accurately defined, resulting in uncertainty concerning the precise moment of release of the anchor plate from the pole face of the core of the just de-energized solenoid.
Accordingly, there is a need in the art for electromagnetically-actuated positioning systems in which the ferromagnetic actuator anchor plate dwell period and release times are precisely known and can be adjusted to predetermined desired times for each particular application.